Electronic musical instrument having a chord detecting function

Abstract

A CPU extracts a specified number of tones, in order of lower pitch from among notes of pressed keys and then determines a chord based on the specified tones so that a musical relationship can be established between the tones corresponding to the depressed keys and the generated chord, thus eliminating incongruity in the performance. In addition, since the chord detection is made based on the specified number of tones, there is no need to play all the constituent notes of the chord. Moreover, by storing chord pattern abbreviations in chord table memory, chords are detected in the manner that of frequently occurring abbreviated chord patterns are prioritized over infrequently occurring chord patterns.

What is claimed is: 
     
       1. An electronic musical instrument comprising: (a) a performance information input means for inputting performance information representing notes corresponding to a sound to be generated;   (b) a first lower tone extracting means for extracting a first predetermined number of notes from among said notes, from lowest pitch to highest pitch;   (c) a chord detection means for detecting a chord based on said extracted notes, said chord detection means having a nondetection condition when a chord is not detected;   (d) an automatic accompaniment means for creating an automatic accompaniment signal based on said detected chord; and   (e) a second lower tone extracting means, responsive to the nondetection condition of said chord detection means, for re-extracting a second predetermined number of notes from among said notes, from lowest pitch to highest pitch, said second predetermined number being less than said first predetermined number and said chord detection means detecting a chord based on said re-extracted notes.   
     
     
       2. An electronic musical instrument according to claim 1, wherein said second predetermined number is less than said first predetermined number by one. 
     
     
       3. An electronic musical instrument comprising: (a) a performance information input means for inputting performance information representing notes corresponding to a sound to be generated;   (b) a lower tone extracting means for extracting a predetermined number of notes from among said notes, from lowest pitch to highest pitch;   (c) a chord detection means for detecting a chord based on said extracted notes;   (d) an automatic accompaniment means for creating an automatic accompaniment signal based on said detected chord; and   (e) a chord table memory having stored therein abbreviated chord patterns representing plural chords respectively, wherein each chord of said plural chords is represented by an abbreviated chord pattern, and wherein said chord detection means detects said chord by comparing said extracted notes with said chord patterns and said abbreviated chord patterns.   
     
     
       4. An electronic musical instrument comprising: a performance information input means for inputting performance information representing notes corresponding to a sound to be generated;   a chord table memory having stored therein chord patterns representing plural chords respectively, wherein at least one of said plural chords is also represented by an abbreviated chord pattern;   a chord detection means for detecting a chord by comparing said performance information with said chord patterns and said abbreviated chord pattern under a condition that said abbreviated chord pattern is prioritized over infrequently occurring one or ones of said chord patterns; and   an automatic accompaniment means for creating an automatic accompaniment signal based on said detected chord.   
     
     
       5. An electronic musical instrument according to claim 4, wherein when said chord table memory stores said abbreviated chord pattern in regard to a predetermined key, said chord detection means having means for transposing said performance information with one of said chord patterns and said abbreviated chord pattern. 
     
     
       6. An electronic musical instrument according to claims 1 or 2, wherein said performance information input means is a keyboard, and said first and second lower tone extracting means correspond to keys belonging to a specified key region of said keyboard. 
     
     
       7. An electronic musical instrument comprising: a performance information input means for inputting performance information representing notes corresponding to a sound to be generated;   a lower tone extracting means for extracting a first predetermined number of notes from among said notes, from lowest pitch to highest pitch, wherein the predetermined number of notes is less than all of said notes;   a chord detection means for detecting a chord based on said extracted notes; and   an automatic accompaniment means for creating an automatic accompaniment signal based on said detected chord.   
     
     
       8. An electronic musical instrument according to one of claims 1 through 5 and 7, wherein said performance information input means is a keyboard. 
     
     
       9. An electronic musical instrument according to claims 1 or 7, wherein said performance information input means is a keyboard, and said lower tone extracting means corresponds to keys belonging to a specified key region of said keyboard. 
     
     
       10. An electronic musical instrument comprising: a keyboard having a plurality of keys that a performer can depress to play a melody and an accompaniment simultaneously;   performance information detecting means for detecting performance information representing key depressions and pitches with respect to depressed keys among said plurality of keys;   musical tone producing means for producing musical tone signals having pitches corresponding to the depressed keys on the basis of said performance information;   chord name detection means for detecting a chord name corresponding to the pitches represented by said performance information;   determining means for determining whether or not said chord name detection means has detected the chord name;   chord name providing means, responsive to the determining means, to provide the chord name detected by the chord name detection means; and   automatic accompaniment means for performing an automatic accompaniment based on said chord name provided by said chord name providing means.   
     
     
       11. A method of determining a chord for an electronic musical instrument, the method comprising the steps of: inputting performance information representing notes corresponding to a sound to be generated;   extracting a first predetermined number of notes from among said notes, from lowest pitch to highest pitch;   detecting a chord based on said extracted notes;   indicating a non-detection condition when a chord is not detected;   re-extracting a second predetermined number of notes from among said notes, from lowest pitch to highest pitch, in response to the non-detection condition, said second predetermined number being less than said first predetermined number;   detecting a chord based on said re-extracted notes; and   creating an automatic accompaniment signal based on said detected chord.   
     
     
       12. A method according to claim 11, wherein said second predetermined number is less than said first predetermined number by one. 
     
     
       13. A method of selecting a chord for an electronic musical instrument, the method comprising the steps of: storing abbreviated chord patterns representing plural chords respectively in a chord table memory, wherein each chord of said plural chords is represented by an abbreviated chord pattern;   inputting performance information representing notes corresponding to a sound to be generated;   extracting a predetermined number of notes from among said notes, from lowest pitch to highest pitch;   detecting a chord based on said extracted notes, wherein the chord is detected by comparing said extracted notes with said chord patterns and said abbreviated chord patterns; and   creating an automatic accompaniment signal based on said detected chord.   
     
     
       14. A method of selecting a chord for an electronic musical instrument, the method comprising the steps of: inputting performance information representing notes corresponding to a sound to be generated;   storing chord patterns representing plural chords respectively in a chord table memory, wherein at least one of said plural chords is also represented by an abbreviated chord pattern;   detecting a chord by comparing said performance information with said chord patterns and said abbreviated chord pattern under a condition that said abbreviated chord pattern is prioritized over infrequently occurring one or ones of said chord patterns; and   creating an automatic accompaniment signal based on said detected chord.   
     
     
       15. A method according to claim 14, further comprising the steps of: storing said abbreviated chord pattern in regard to a predetermined key; and   transposing said performance information with one of said chord patterns and said abbreviated chord pattern.   
     
     
       16. A method of selecting a chord for an electronic musical instrument, the method comprising the steps of: inputting performance information representing notes corresponding to a sound to be generated;   extracting a first predetermined number of notes from among said notes, from lowest pitch to highest pitch, wherein the predetermined number of notes is less than all of said notes;   detecting a chord based on said extracted notes; and   creating an automatic accompaniment signal based on said detected chord.   
     
     
       17. A method of selecting a chord for an electronic musical instrument, the method comprising the steps of: providing a keyboard having a plurality of keys that a performer can depress to play a melody and an accompaniment simultaneously;   detecting performance information representing key depressions and pitches with respect to depressed keys among said plurality of keys;   producing musical tone signals having pitches corresponding to the depressed keys on the basis of said performance information;   detecting a chord name corresponding to the pitches represented by said performance information;   determining whether or not the chord name has been detected;   providing the chord name to an automatic accompaniment portion of the electronic musical instrument if the chord name has been detected; and   performing an automatic accompaniment based on the provided chord name.